1) Field of the Invention
The present invention relates to the manufacture of airfoils and, more particularly, to an airfoil box formed of multiple unitary partial-shell structures.
2) Description of Related Art
Certain structural parts have conventionally been manufactured by joining a number of preformed structural members. For example, in the aircraft industry, wings are often manufactured by separately forming, and then joining, one or more skins, stringers, ribs, bulkheads, and spars. The skins, which are typically large laminar members, form the outer contoured airfoil of the wing, and the stringers, ribs, bulkheads, and spars provide a stiff internal framework that supports the skins. The various members are joined by drilling holes through adjacent members and installing rivets or other fasteners in the holes. According to this conventional method, each wing includes many joined components, and each component must be joined to the others. Often, at least some of the joints must be formed manually, for example, where the joints are formed at internal locations in the wing that are difficult to access using conventional automated joining machines. The formation and fastening of the various components can be a time-consuming process. Further, the fasteners and the connection portions of the various components, which are typically overlapped for fastening, contribute to the total weight of the final wing.
Thus, there exists a continued need for an improved manufacturing process and improved parts formed thereby. The manufacturing process should reduce the number of fasteners or other joining members that must be installed, thereby potentially reducing the time for manufacture and the weight of the final product. Further, the process should be adapted for automated manufacturing processes and for use in manufacturing structural parts of different configurations.